Steam generator



Sent. 19, 1933.

W. G. NOACK STEAM GENERATOR Filed May 20. 1930 5w 2 g g T" g E 6 5b ilInventor Patented Sept. 19, 1933 1,927,649 STEAM GENERATOR Walter GustavNoack, Baden, Switzerland, as-- signor to Aktiengesellsohaft BrownBoveri & Cie, Baden, Switzerland, a joint stock company of SwitzerlandApplication f in Germany 14 Claims.

This invention relates to steam generators, and it hasparticularrelation to injection steam generators as described, forinstance, in my 00- pending application, Serial No. 268,493 whichmatured into Patent 1,817,419. In such steam generators a small quantityof steam, called exciter steam, is superheated and applied to water, forinstance, by injection of one medium into the other, to evaporate thewater by the superheat of the admitted steam and producing thereby anenlarged quantity of steam; the soobtained larger quantity of steam isagain superheated and utilized to convert a further quan' tity of waterinto steam, thus further increasing the amount of available steam; andthis process is successively repeated untilthe required quantity ofsteam is generated.

' Among the objects of the present invention is the provision of animproved steam generator of the foregoing type having specialarrangements for securing eflicient and desirable operating conditionsat no load, as well as high load operation.

The foregoing and other objects of the invention will be apparent fromthe following description, reference being made to the accompanyingdrawing which illustrates diagrammatically one embodiment of theinvention.

As shown in the drawing, the multi-stage injection steam generatorcomprises a ,reservoir 4 holding water in the bottom part and a,

quantity of steam under pressure in the top part. Feed Water is suitablysupplied to the reservoir 4 by a feed water line 5 through a water preeheater 5a which preheats the water before it is delivered to thereservoir. Included in the feed water pipe 5 is also a valve 51)actuated by a regulating device which is connected to I the steam spacein the reservoir 4 to vary the admission or" feed Water to the reservoirdepending on the pressure therein, as will be explained hereafter.

To generate steam a small quantity of steam is drawn by steam pump 6from reservoir 4 and F forced under pressure through a first superheator7 into a first vaporizer 8. The vaporizer 8 is supplied with water fromthe reservoir 4 by, means of a water pump 9 which forces water through adelivery line 11 and discharges it the vaporizer 8 in the form of aspray. The steam from the; superheater 7 and the water from the deliveryline 11 are thus brought ,into intimate contaotvaporizing a largequantity of water and producing a 'large quantity 5 of wet steam.Excessive injection water flows May 20, 1930, Serial No. 453,941, and

May 31, 1929 back to the reservoir 4 from the vaporizer 8 through areturn line 12. f v

' The increased quantity of wetsteam in vaporizer 8, being under thepressure of the steam pump 6, is forced from the vaporizer 8 through, asecond superheater 13, where it is .againsuperheated, into a secondvaporizer 14where the superheated steamconverts additional water iromline 11 into steam. This process is' repeated in each of the successivevaporizer vessels 1'? and 18 until the" required quantity of steam isgenerated inthe last vaporizer 19 iromlwhere the wet steam flows througha main super: heater 21 andfoutlet valve 22 to the steam con: sumingdevices. lThus, alvery smalllquantityjof excitation steam irom thereservoir 4 is fsufiicient to produce allarge quantity 'oisteam of suchpressure as may'bq'desired' The" heat is supplied to thegsuperheatercoils 13,: 16, 18, ,21 by the hot combustion gases passing'throughgasduct 3 in whichthejooilsare mounted, the reservoir 4 being outside'ltheduct. wTo initially start it the operation, an auxiliary boilergl,heated by the hot combustion ,gases in duct 3, is.pro-, vided to producean initial amount v of steam which is delivered through heatingfcoilfzto the steam space ofreservoir 4 .for starting the v vaporizationprocess in the series of vaporizer stages. 7 The pressure of this exciterv boiler 1 may be made sufiiciently large 'to force the steam flowthrough the several stages, in which case pump 6 wouldnot benecessarybut operation with a pump .is preferable, because under normalconditions reservoir4 has always enough steam to start operation. Fornormal operatio'n the steam generated .by the vaporizer stages is madeabout sufiicient to'supply thenormal load. The reservoir is utilized asa buffer or storer for taking care of excess steam demand or overloads,and of excess steam generation by "the vaporizer stages whenthesteamdemand is below normal. This is eflected by the'provision of abypass conduit with non-return ;valv e'123 permitting steam flow fromthe outlet side of the main superheater 21 (before shut-off valve of thesuperheater 21 and sol-that non-return 110 the pressure in the finalsuperheater 21 will drop below that of the reservoir 4 and the nonreturnvalve 24 will be opened by the higher pressure on the reservoir sidethereby permitting Wet steam to flow from the reservoir 4 directlythrough the superheater 21 to the point of consumption.

If the steam consumption decreases, thetotal amount of steam generatedwill increase the steam pressure in the superheater 21 above that in'thereservoir 4 and the non-return valve 23 will open to permit a return ofthe excess superheated steam to the water space of reservoir 4 in whichit is' condensed. When the steam generator is being shut down by closingvalve 22, or when the supply is greatly in excess of the demand, ineither of which cases large quantities of steam are returned through thenon-return valve 14 to the container 1, an excessivepressure (blowingoff) in the latter may be avoided by the supply of excess feed water tothe container. Since in comparison with ordinary boilers the containeroperates with greatly varying water levels, the level of the water innormal'operation, will usually be kept relatively low and when closingdown-or during periodsof very low demand a large quantity of feed'w'aterwill be introduced which condenses the excess steam, TheeXtra feedwater, in the same way as'the normal feed water, is supplied by feedwater pipe 5 through'the water preheater 5a in the fiue duct 2 to thecontainer 1. The, admission ofexcess feedwater is automaticallyregulated by the pressure regulator which controls the feedregulator 5bto supply more water to the container ,1 when a predetermined pressurein the said container is e5:- ceeded. The regulation'of the feed Waterin normal operationis effected in the usual manner by a regulatordependent on the alteration of watenlevel in the container.

Although but one embodiment of the present invention has beenillustrated and described, it willfbe apparent that various changes andmodifications may be made therein without departing from theispirit oftheinvention or from the scope of the appendedclaims.

The invention claimed is: 1 1.' In a steam generating installation, areservoir for holding, preheated water and steam, a

pump connected with said'reservoir to withdraw steam therefrom, apreliminary superheater receiving the steam from said pump, a primaryvaporizer receiving the steam from said superheater, a plurality ofsecondary superheaters, a plurality of secondary Vaporizers, saidsecondary superheaters and said secondary Vaporizers being connected inseries with said-primary Vaporizers, meansconnected with said reservoirfor supplying water to all of said Vaporizers, a final superheaterreceiving and heating the steam from all of said Vaporizers, and meansconnecting the steam space of said reservoir directly with the inletside of said final superheater during periods of increased demand forsteam.

2. In a steam generating installation, a reservoir for holding preheatedwater and steam, a

pump connected withsaid reservoir to withdraw steam therefrom, apreliminary superheater re- 'ceiving the steam from said pump, a primaryvaporizer receiving the steam from said superheater, a plurality ofsecondary superheaters, a

plurality of secondary Vaporizers, said secondary superheaters and saidsecondary Vaporizers being connected in series with said primaryvaporizer, means connected with said reservoir for supplying watertoall'of said Vaporizers, a final'superheater receiving and heating thesteam from all of said Vaporizers, and means connecting the outlet sideof said final superheater directly with the water containing space ofsaid reservoir during periods of decreased demand for steam,

3. In a steam generator, a steam generating circuit including areservoir for holding proheated water and steam water from the saidpreheater, a pump connected with said reservoir to withdraw steamtherefrom, a preliminary superheater receiving the steam from said pump,a primary vaporizer receiving the steam from said superheater,aplurality of secondary superheaters, a plurality of secondaryVaporizers, said secondary superheaters and said secondary vaporizersbeingconnected in series with said primary vaporizers, means connectedwith said reservoir for supplying water to all of said vaporizers, and afinal superheater receiving'and heating the steam from all of saidVaporizers to the temperature desired for use; and a steam supplycontrol circuit including a non-return valve for passing steam from thesteam space of said reservoir directly into said final superheater during periods of increased demand for steam, and a non-return valveconnecting the outlet side oisaid final superheater directly with thewater containing space of said reservoir during periods of decreaseddemand for steam.

4. In asteam generator system, a reservoir for holding preheated waterand steam, a main superheater having an inlet and an outlet, aninjection steam vaporizer connected between the steam soaoe of saidreservoir and the inlet of said main superheater, said vaporizercomprising a vessel having a water inlet for supplying Water to thevessel, superheater tubes connected between the reservoir and saidvessel arranged to superheat steam received from said reservoir anddischarge it in superheated condition into the vessel to vaporize watersupplied thereto, and a steam outlet for delivering the resultant steamin said vessel into said main superheater, means associated with saidreservoir to produce a steam flow'from the reservoir through thevaporizer to the main superheater, generating in the vaporizeradditional steam joining said flow, a bypass conduit connecting thesteam space of said reservoir to the inlet side of said mainsuperheater, a bypass conduit connecting the water space or" saidreservoir to the outlet side of said superheater, and valve meansassociated with said injection steam vaporizer connected between thesteam space of said reservoir and the inlet of said main superheater,said vaporizer comprising a vessel having a water inlet for supplyingWater to the vessel, superheater tubes connected between the reservoirand said vessel arranged to superheat steam received from said reservoirand discharge it in superheated condition into the 'vessel to vaporizewater supplied theretm and a steam outlet for delivering the resultantsteam in said vessel into said main superheater, means associated withsaid reservoir to produce a steam flow from the reservoir through thevaporizer to the main superheater, generating in thevaporizer additionalsteam joining said flow, a bypass conduit connecting the'steam spaceof-s'aid reservoir to the inlet'side of said main superheater includingvalve means to permit flow of wet steam from the reservoir to the mainsuperhe'ater only in response to lower pressure at the holding preheatedwater and steam; a main superheater having an inlet and an outlet, aninjection steam vaporizer connected between the steam space of saidreservoir and the inlet'of said main superheater, said vaporizercomprising a vessel having a water inlet for supplying water to thevessel, superheater tubes connected between the reservoir and saidvessel arranged to 'superheat steam received from'said reservoir and idischarge it in superheated condition into the vessel to vaporize watersupplied thereto, and a steam outlet for delivering the resultant steamin said vessel into said main superheatenmeans associated with saidreservoir to produce asteam flow from the reservoir through thevaporizer to the main superheater, generating in the vaporizeradditional steam joining said flow, conduit means including a non-returnvalve opening in response to decrease of the pressure of the steamsupply connecting the steam space of the reservoir to the inletof saidsuperheater to supply and conduit means including a non-return valveopening in response to excess of steam supply connecting the outlet sideof the superheater to the water space of the reservoir causingsuperheated steam to flow from the superheater to the water space of thereservoir." 7

7. In a steam generator system,"a reservoir for holding preheated waterand' steam, a mainsuperh'eater having an inlet and an outlet, aninjection steam vaporizer connected between the steam space of saidreservoir and theinlet of said main superheater, said vaporizercomprising a vessel having a water inlet for supplying water to thevessel, superheater tubes connected .between the reservoir and saidvessel arranged to superheat steam received from said reservoir anddischarge it in superheated condition into the vessel to vaporize watersupplied thereto, and 'a steam outlet for delivering the resultant steamin said vessel into said main superheater, means associated with saidreservoir to produce a steam flow from the reservoir through thevaporizer to the main superheater, generating in the vaporizeradditional steam joining said flow, and a bypass conduit connecting thewater space of said reservoir to the outlet side of said superheaterincluding valve means to permit flow of superheated steam from saidsuperheater to the waterspace of said reservoir only in response tohigher pressure at the superheater outlet than a corresponding pressurein said reservoir. H

water space of said resflow from the reservoir through side of saidmulti-stage vaporizer'than 8. In a steam -generator system,- areservoirfor holding preheated water and steam; a main sue perheaterhaving andinlet and an outlet, a multistageinjection steam vaporizerconnected be- I tween the'stea'm space or said reservoir 'andthe inletof said main superheater, said vaporizer comprising a plurality ofserially arranged-vaporizerstages, each of said stages'comprising avaporizer vessel having a water inletfor supply- 7 ing water to'thevessel, superheater tubes arranged to superheat received steam anddischarge it in superheated condition into the vessel to vaporize watersuppliedthereto',anda steam outletfor delivering the resultant steam insaid vessel, the steam outlet ofthe vaporizernvessel of each stage beingconnected-to the inlet of the superheater tubes of the followingstage','-means' associated with said reservoir to produce. a steam thesuccessive stages to the main superheater, generatingin each stageadditional steam joining saiidflowfa' bypass conduit'connecting thesteam space of said reservoir to the inlet side of'said main superheater, a bypass conduit connecting the water space of said reservoirto the outlet side of said superheater, and valve means associated withsaid conduits'arranged" to permit flow of wet steam from the reservoirthrough its conduit :to the main superheater, and flowN-ofsuperheatedsteam fromjsaid superheater to the water'space of said reservoirdepending on the'pressurecon-' ditions in the system.

9. In a steam generator system',ia,reservoir'for holdingpreheated waterand steam, a "main superheater having an inlet and an: outlet, amulti-stage injection steam vaporizer connected between the steam spaceof said reservoirand the inlet of said main superheater, said vaporizercomprising a plurality of serially arrangedvaporizer stages, each ofsaid stages'comprising a vaporizer vessel having awaterinlet-ior.supply- 1 7 ing water to the vessel, superheater tubesarjranged to superheat received steam and-diswet steam from thereservoir to the superheater,

charge it in superheated condition into the yessel to vaporizewatersupplied thereto,iand a steam-outlet for delivering-the resultant steamin said vessel, the steam outlet of the vaporizer vessel of each stagebeing connected to the inlet of the superheater tubes of 1 the'following stage,

means associated with said' reservoir for normally maintaining a higherat the pressure at the inlet outlet'side thereof to produce a steam-flow from the reservoir through the successive stages to the mainsuperheater, generating i'nfeachstage additional steam" joiningsaidflow, conduit means including a non-return valve opening in response toinsufficient steam supply connecting I including a non-return valveopening in response to excess of steam supply connecting'the outlet sideof the superheater to the water spaceof the reservoircausing superheatedsteam to how from the superheater to the water space of the reser:

voir.

for holding preheated water and steam; a main superheater having aninlet and an, outlet, a

10. In a stearn generator-system;- a reservoir multi-stage injectionsteam vaporizer "connected between the steam space or said'reservoir andthe inlet or" said .main superheater, said vapor izer comprising aplurality of serially arranged said reservoir water, to the water inletsof said vaporizer vessels and returning excess water in the vaporizervessel'to said reservoir, means associated with said reservoir fornormally maintaining afhigher pressure atthe inlet side of saidmulti-stage vaporizer than at the outlet side thereof to produce a steamflow. from the reservoir through the successive stages to the main 1superheater, generating in each stage additional steam joining saidflow, a bypass conduit conmeeting the steam space ofpsaidreservoir tothe inlet side of said main superheater including valve means to permitflow of wet steam from the reservoir to the main superheater only inresponse to lower pressure at the superheater inlet than a correspondingpressure in said reservoir, and a bypass. conduit connecting the Waterspace of said reservoir to the outlet side of said superheater includingvalve means to permit now of superheated steam from said superheater tothe Water space of said reservoir only in response to higher pressure atthe superheater outlet than a corresponding pressure in said reservoir.

11. In a steam generator system, a reservoir for. holding preheatedwater and steam, a mainsuperheater having an inlet and an outlet, a

, multi-stage injection steam vaporizer connected between the steamspace of said reservoir and the inlet of said main superheater, saidvapor- .izer comprising a plurality'of serially arranged vaporizerstages, each of said stages comprising avaporizer vessel having a waterinlet for supplying water to the vessel, superheater tubes arranged tosuperheat received steam and discharge it in superheated condition intothe vessel to vaporize water supplied thereto, and a steam outlet fordelivering the resultant steam in said vessel, the steam outlet of thevaporizer vessel of each stage being connected-to the inlet ofgthesuperheater tubes of the following stage,

means associated with said reservoir to produce a steam flow from thereservoir through the successive stages to the main superheater,generating in each stage additional steam joining said how, a bypassconduit connecting the steam space of said reservoir to the inlet sideof said main superheater including valve means to per mit flow of Wetsteam from the reservoir to the main superheater only in responsetolower pressure at the superheater inlet than a corresponding pressurein said reservoir, a bypass conduit connectingthe water space of saidreservoir to, the outlet side of said superheater including valve meansto permit flow of superheated steam from said superheater to the waterspace of said reservoir only in response to higher pressure at thesuperheater outlet than a corresponding pressure in said reservoir, andashutoff valve controlling the outflow of steam from the outlet side ofsaid superheater to the steam consuming devices for causing steam fromthe superheater outlet to flow to the water space of 7 the reservoir toheat it up and build up the pressure therein.

7 12. Ina steam generator system, a reservoir for holding preheatedwater and steam, a main superheater having an vinlet and an outlet, avmulti-stage injection steam vaporizer connected between the steamspace'of said reservoir and the inlet of said main superheater, saidvaporizer comprising a plurality of serially arranged vaporizer stages,each of' said stages comprising a vaporizer vessel having a water inletfor supplying water to the vessel, superheater tubes arranged tosuperheat received steam and discharge it in superheated condition intothe vessel to; vaporize water supplied thereto, and a steamoutlet fordelivering, the resultant steam in said vessel, the steam outlet of. thevaporizer vessel of each stage being connected to the inlet of g thesuperheater tubes of the following stage, means asso-- ciated withsaidreservoir for normally maintaining a higher pressure ,at' the inlet sideof said multi-stage vaporizer than at theoutlet side thereof to producea steam flow from the reser voir through the successive stages to themain superheater, generating in each stage additional steamvioiningsaidflow, a bypass conduit'connecting the steam space of said reservoirto the inlet side ofsaid main superheater including valve means topermit flow of wet steam from the reservoir to the main superheater onlyin response to lower pressure atthe superheater inlet than'acorresponding pressure in said res V ervoir',-,and a bypass conduitconnecting the water space of said reservoir to theoutlet side of saidsuperheater including valve means to permit flow of superheated steamfrom said superheater to the Water space of said reservoir onlyinresponse to higher pressure at the super- I heater outlet than acorrespondingpressure in said reservoir. 1 13. In a steam generatorsystem, a reservoir for holding preheated water and steam, a mainsuperheater having an inlet and an outlet, a

multi-stage injection steam vaporizer connected between the steam spaceof saidreservoir and the inlet of said main superheaten said va porizercomprising a plurality of serially arranged vaporizer stages, each ofsaid stages comprising a vaporizer vessel having a water inlet forsupplying water, to the vessel, superheater tubes arranged to superheatreceived steam and discharge it, in superheated condition into thevessel to vaporize water supplied thereto, and .asteam outlet fordelivering the result ant steamin said vessel, the steam outlet of thevaporizer ,vessel of each stage being connected to the inlet of thesuperheater tubes of the following stage, means for supplying from the,

Water space of said reservoir water to the water inlets of saidvaporizer vessels, means associated with said reservoir to produce asteam flow from the reservoir throughcthe successivestagesv to the mainsuperheater, generating in each stage additional steam joining saidflow, a bypass con duit connecting the steam space of said reservoirtothe inlet side of said main superheater including valve means to permitflow of wet steam from the reservoir to the main superheater onlyinresponse to lower pressure at the superheater inlet than a correspondingpressure in said reservoir, abypass conduit connecting the water spaceof said reservoir to the outlet side of said superheater including valvemeans to permit flow of superheated'steam from said superheater to thewater space of said reservoir EEO only in response to higher pressure atthe super- 7 heater outlet than a corresponding pressure in saidreservoir, and means for variably supplying feed water intosaid'reservoir to condense excess steam flowing from the superheater tosaid reservoir.

14. In a steam generator system, a reservoir for holding preheated waterand steam, a main superheater having an inlet and an outlet, amulti-stage injection steam vaporizer connected between the steam spaceof said reservoir and the inlet of said main superheater, said vaporizercomprising a plurality of serially arranged va-' porizer stages, each ofsaid stages comprising a vaporizer vessel having a water inlet forsupplying water to the vessel, superheater tubes arranged to superheatreceived steam and discharge it in superheated condition into the vesselto vaporize water supplied thereto, and a steam outlet for deliveringthe resultant steam in said vessel, the steam outlet of the vaporizervessel of each stage being connected to the inlet of the superheatertubes of the following stage, means for supplying from the water spaceof said reservoir water to the water inlets of said vaporizer vessels,means associated with said reservoir to produce a steam flow from thereservoir through the successive stages to the main superheater,generating in each stage additional steam joining said .flow, a bypassconduit connecting the steamspace of said reservoir to the inlet side ofsaid main superheater including valve means to permit flow of wet steamfrom the reservoir to the main superheater only in response to lowerpressure at the superheater inlet than a WALTER GUSTAV NOACK. I

